Mine is "Robin Hood: Prince of Thieves" (with Kevin Costner)
I loved the scenes with the "forestmen" & the attack on their forest hideout.....reminded me a lot of lego battles which took place in my bedroom many years ago.

Yes, Prince of Thieves was one of my favourite Castle movies, too. As a matter of fact it kept me buying LEGO in 1992 although I was already way older than 12 (15, to be exact). After I had seen the movie I went to the local Wal Mart and bought the Black Knight's Castle 6086 (for the fortress of the Sheriff of Nottingham).

There is only one Robin Hood movie: Errol Flynn in The Adventurers of Robin Hood. Great cast: Flynn, Olivia DeHaviland, Basil Rathbone, and Claude Rains. Properly keeps it moving, breezy and light-hearted even if Merry Olde England looks a bit Southern California to me.

Let me single out the Kevin Costner version as particularly bad - Costner has a limited range, and being a leader of men isn't within that range (notice how Sean Connery projects that missing quality with only a minute of screen time), not to mention PCing the poor story to death, and Alan Rickman playing the sheriff for comedy relief. But then, I've listed some films that are Not Well Regarded below - it's a matter of what age you were when you first saw the film in question.

Some others of interest:

The Vikings: Kirk Douglas and Tony Curtis dual it out as a very (very!) loose rendition of the Ragnar Brothers.

Ivanhoe: Elizabeth Taylor when she was young and thin. George Sanders as the slimy villian. Another hokey movie from the 50's, but I like it.

Alexander Nevsky: Sergei Eisenstein classic. Music by Prokofiev. Yeah, he seems rather a socialistic kinda guy in this rendition (whaddya want with Joe Steel looking over your shoulder in 1938), but the confrontation between the Teutonic Knights and Nevsky at the Ice Slaughter is fantastic.

Seven Samurai: Akira Kurosawa and Toshiro Mifune. I think Ran will appeal to more people with massive formed units in color moving about the field (absolutely stunning).

Braveheart: okay, familiarity breeds contempt, because I can spot so many inaccuracies, but hey, it's Hollywood.

Monty Python and the Holy Grail: An extremely silly movie that actually understands the legends and history more than might be expected. It was also more influential than you might think since just about every medieval fantasy or history that followed it tried to capture it's murky, dark look.

The Black Shield of Falworth: Try to watch this when you are young (you'll laugh more than be inspired as an adult). It has a special place in my heart, but boy is it awful!

Redwine the Ribald: Stare long enough into the abyss...
Two-Tonic Tippler: ...and you spit into it.

I actually like the Kevin Costner one too, but it takes a much lower spot on my list of favorites - it just seems a little too... staged? I'm not sure what the word is, but I just seems too much like a movie - I don't really get into it. For some reason, the old B&W version always stops my channel surfing - I can't explain.

Other than that, Braveheart is also one of my favorites - I know it's full of inaccuracies and heavily exagerated, but I can't help loving it - I think it's very well done.

Knight Templar n. pl. Knights Templars or Knights Templar1.A member of an order of knights founded about 1118 to protect pilgrims in the Holy Land during the Second Crusade.

I think my favourite Castle movie must be either A Knight's Tale or The Court Jester (1956), featuring Danny Kaye, Basil Rathbone and Angela Lansbury. This movie is absolutely fantastic. I love the whole purple pimpernel birthmark thing. Its easily the funniest Castle movie outside of Monty Python and the Holy Grail.

I like A Knight's Tale because it is so deliberately innacurate. This movie works because it doesn't try to take itself seriously. Mark Addy and Paul Bettnay are absolutely hilarious, and Shannyn Sossamon is hot! What more could you want! The characters are absurd, the plot is non-existent, and everything else is completely cliche, but the whole thing turns out to be alot of fun!!

Its actually ironic that I really don't like Braveheart! This movie just takes itself too seriously. Mel Gibson just takes too many liberties with history to be taken seriously in this one!

Gotta go with the majority and say that I love Errol Flynn's (Californian ) Robin Hood. A Knight's Tale, while not to be recommended if you desire anything particularly serious, is good too. I prefer the Princess Bride myself, but that's just a matter of comedic taste.

Although not quite medieval, I also enjoy the Lord of the Rings movies, although if you're looking to avoid an accuracy argument, steer WELL clear of the those movies if I'm in the neighbourhood.

The medieval-ish movies from the 50s are good for light-hearted fun, and rather corny-looking knights, but they're good enough if there's nothing else going on.

First off, I should note that I like all of my favorites due to scenery, costumes, and story, rather than for historical accuracy (if I want a history lesson, I'll pick up a history book). That being said, some of my favorites, in no particular order, are:

1. The 13th Warrior - I actually probably like the book better. Either way, I love the way they depict people from two entirely different cultures interacting.
2. King Arthur - Yes, the new one... the one that everybody else on Earth hated. So sue me. I loved the story, regardless of inconsistency with history or Arthurian Legend, and the costumes were fantastic, in my opinion. Let's not forget Kiera Knightley in leather straps and full tribal warpaint... mmm... I actually wanted my wedding to be based on the ceremony at the end, but I doubt that will come to fruition.
3. Braveheart - I actually like this one less than I used to, and usually stop watching after the first half, but I love the music, costumes and scenery, and it has a bit of humor to it to, which I enjoy.
4. Dragonheart - This is a really silly movie, but I loved it as a kid, so I still get a kick out of it from time to time.
5. Lord of The Rings Trilogy - These gave great visuals for the books, which I also love.
6. Merlin - I'm talking about the cheesy, made for t.v. movie. It was a fun story nonetheless.

There are probably tons more that I'm forgetting, but these are the ones that I came up with off the top of my head.

"Always do what you want, and say what you feel, because those who mind don't matter, and those who matter don't mind." ~ Doctor Suess

I put together a list of medieval themed movies (I myself printed the list out & will swing by the local video stores to rent some)

EARLY MEDIEVAL (500 to 1050 AD)The Knights of the Round Table
Sword of Lancelot
First Knight [SPRING 96]
Excalibur [SPRING 96]
Camelot
Prince Valiant
Sword of the Valiant
The Sword in the Stone (Disney animation)
Monty Python and the Holy Grail (932 AD)
The Green Knight
Prince of Jutland
Merlin and the Sword
Merlin of the Crystal Cave
Flight of the Dragons (animated)
The Sword and the Sorcerer (Disney)
Dragonslayer
Tristan et Iseuldt
The Vikings
The Littlest Viking
The Longships
Eric the Viking
The Norseman
The Black Shield of Falworth
The Black Arrow
Alfred the Great (late 800s England)

I should add a couple that come a little later historically--Henry V (the '80's version by Branaugh) and A Man for All Seasons. Both great movies. Of course any of the movie-i-zations of Shakespeare's plays would make my list.